Aromatics extraction (Edeleanu process): In the classical Edeleanu process used for dearomatisation of kerosene-range stocks, the solvent employed is:

Introduction:
Before modern extractive-solvent systems became common, the Edeleanu process was widely cited for removing aromatics from kerosene-range fractions to improve smoke point and colour. The heart of any extraction process is the solvent that selectively dissolves the target species. This question asks you to identify the characteristic solvent used by the Edeleanu route.

Given Data / Assumptions:

• Feed: kerosene/naphtha-range cuts requiring dearomatisation.
• Goal: reduce aromatics to improve burning quality (e.g., higher smoke point).
• Legacy process name: Edeleanu.

Concept / Approach:
The Edeleanu process uses liquid sulphur dioxide (liquid SO2) as the selective solvent. Liquid SO2 preferentially dissolves aromatics over paraffins/naphthenes at controlled temperature, enabling phase separation and recovery. Alternative solvents (furfural, phenol, sulfolane) are associated with other extraction processes, typically for lube base stocks or aromatics recovery but not the original Edeleanu scheme for kerosene dearomatisation.

Step-by-Step Solution:

Verification / Alternative check:
Historic refining texts and exam guides explicitly state liquid SO2 for the Edeleanu process, distinguishing it from furfural or phenol extraction used in lube refining.

Why Other Options Are Wrong:

• Furfural/Phenol/Sulfolane: Valid extraction solvents in other units, not the Edeleanu original.
• Propane: Used in deasphalting or dewaxing contexts, not aromatic extraction.

Common Pitfalls:
Assuming any polar solvent fits all extraction processes; names matter in legacy refining terminology.

Final Answer:
Liquid SO2